Production and use of new thermoplastic polyurethane elastomers based on polyether carbonate polyols

ABSTRACT

The invention relates to a method for producing a thermoplastic polyurethane elastomer based on polyether carbonate polyols. The method comprises a first step, in which at least A) an organic diisocyanate and B) a polyol having a number-average molecular weight Mn&gt;=500 and &lt;=5000 g/mol are reacted to form an isocyanate-terminated prepolymer. In a second step, the prepolymer is reacted with C) one or more chain extenders having a molecular weight&gt;=60 and &lt;=490 g/mol and optionally D) a monofunctional chain stopper or E) an organic diisocyanate, wherein optionally at least F) one catalyst is used in the first and/or second step.; The molar ratio of the sum of the isocyanate groups from A) and, if applicable, E) to the sum of the groups reactive to isocyanate in B), C), and, if applicable, D) is &gt;=0.9:1 and &lt;=12:1, and component B) contains at least one polyether carbonate polyol, which can be obtained by adding carbon dioxide and alkylene oxides to H-functional starter substances. The invention further relates to a thermoplastic polyurethane elastomer produced in accordance with the method according to the invention, the use of said thermoplastic polyurethane elastomer to produce extruded or injection molded items, and the items produced by extrusion or injection molding.

The invention relates to a process for the production of a thermoplasticpolyurethane elastomer based on polyether carbonate polyols. Theinvention further relates to a thermoplastic polyurethane elastomerproduced by the process of the invention, the use thereof for theproduction of extruded or injection-molded items, and also the itemsproduced via extrusion or injection molding.

Thermoplastic polyurethane elastomers (TPUs) are of great importance inindustry because they have excellent mechanical properties and can beprocessed by thermoplastic methods at low cost. Their mechanicalproperties can be varied widely via the use of different chemicalstructural components. Kunststoffe [plastics] 68 (1978), pp. 819-825 andKautschuk, Gummi, Kunststoffe [Rubber, Natural Rubber, Plastics] 35(1982), pp. 568-584 provide overviews of TPUs, and their properties anduses.

TPUs are composed of linear polyols, mostly polyester polyols, polyetherpolyols, or polycarbonate polyols, organic diisocyanates, andshort-chain compounds having two isocyanate-reactive groups (chainextenders). It is also possible to add catalysts in order to acceleratethe formative reaction. The molar ratios of the structural componentscan be varied widely, and by this means it is possible to adjust theproperties of the products. Products obtained have a wide range of Shorehardness, depending on the molar ratios of polyols to chain extenders.The thermoplastically processible polyurethane elastomers can beconstructed either stepwise (prepolymer process) or via simultaneousreaction of all of the components in one stage (one-shot process). Theprepolymer process begins by producing an isocyanate-containingprepolymer from the polyol and the diisocyanate, and in a second stepthis is reacted with the chain extender. The TPUs can be producedcontinuously or batchwise. The best-known industrial productionprocesses are the belt process and the extruder process.

TPUs based on polyethylene oxide polyols and/or on polypropylene oxidepolyols (C2 and, respectively, C3 polyether polyols) can be produced viapolymerization of ethylene oxide and/or propylene oxide by knownprocesses with KOH catalysis or multimetal cyanide catalysis DMCcatalysis), and feature a good overall property profile. Particularmention may be made of rapid solidification after injection molding, andalso very good hydrolysis resistance and microbial resistance of theresultant manufactured components. These TPU materials requireimprovement in respect of mechanical properties, e.g. tensile strength,tensile strain value, and abrasion resistance, and also thermalproperties, e.g. heat resistance. These improvements have hitherto beenachieved by way of example via the use of polyester polyols,polycarbonate polyols, or C4-polyether polyols (polytetramethyleneglycols). However, the two last-mentioned polymeric polyols have acomplicated production process and are composed to some extent ofexpensive starting materials, and are therefore also markedly moreexpensive than C2- or C3-polyether polyols. Polyester polyols have thedisadvantage of susceptibility to hydrolysis.

DE 10147711 A describes a process for the production of polyetheralcohols made of oxirane compounds in the presence of DMC catalysts andof a moderator gas, e.g. carbon dioxide, carbon monoxide, hydrogen, anddinitrogen oxide. The low pressures used during the synthesis lead tomaximal incorporation of CO₂ of 20 mol %, and the number of carbonateunits present in the polyether polyols is therefore very small. Theresultant polyether polyols can also be used for the production ofthermoplastic polyurethane elastomers, but the very small proportion ofcarbonate units is unlikely to give any improvement of properties.

In J. Appl. Polym Sci. 2007, Vol. 104, pp. 3818-3826. S. Xu and M Zhangdescribe the production of elastomers based on polyethylene carbonatepolyols which are produced via copolymerization of ethylene oxide withCO₂ in the presence of a polymer-supported bimetal catalyst. The highproportion of units resulting from ethylene oxide in the elastomer leadsto highly hydrophilic properties which make these materials unsuitablefor many application sectors.

WO2010/115567 A describes the production of microcellular elastomers viareaction of an NCO-terminated prepolymer, produced from an isocyanateand a first polyol, with a second polyol with a number-average molarmass M_(n) of from 1000 to 10 000 g/mol and a chain extender with amolar mass below 800 g/mol. The microcellular structure is generated viathe use of chemical or physical blowing agents, for example water.Polyols used can be polyether carbonate polyols produced viacopolymerization of CO₂ and alkylene oxides. Microcellular structuresbrought about via the use of blowing agents are undesirable when TPUsare processed in injection-molding machines and when extrusion processesare used, because they give a lower level of mechanical properties, inparticular tensile strength and tensile strain at break, and/or defectsarise in the production of foils.

EP 1 707 586 A discloses the production of polyurethane resins Which arebased on polyether carbonate diols produced via transesterification ofcarbonate esters, e.g. dimethyl carbonate, with polyether diols having amolar mass below 500 g/mol. A complicated, 2-stage synthesis is used toproduce the products. This lengthy transesterification process oftenleads to undesired product discoloration and, because of side reactions(elimination of water with formation of double bonds) to OHfunctionalities <2 (mostly from 1.92 to 1.96), thus producing TPUproducts with relatively low molecular weight. The level of mechanicalproperties is then therefore also lower than for glycols with high OHfunctionality (from 1.98 to 2.00).

It was therefore an object of the present invention to provide a processfor the production of low-cost thermoplastic polyurethane elastomerswhich have a good overall property profile and also a particularly highlevel of mechanical properties, and are thus suitable for a wide rangeof applications. A particular intention is that the TPUs produced havenot only increased tensile strength but also particularly low abrasionvalues and improved heat resistance in comparison with the correspondingTPUs known from the prior art, based on pure C2- or C3-polyetherpolyols, or else based on the polyether carbonate diols known from theprior art.

The invention achieves said object via a process for the production of athermoplastic polyurethane elastomer comprising

a first step in which at least

-   A) one organic diisocyanate comprising two isocyanate groups,-   B) one polyol with number-average molar mass M_(n)≧500 and ≦5000    g/mol, which has two isocyanate-reactive groups,    are reacted to give an isocyanate-terminated prepolymer,    and a second step in which the prepolymer is reacted with-   C) one or more chain extenders with molar mass ≧60 and ≦490 g/mol,    which have two isocyanate-reactive groups,-   and optionally-   D) a monofunctional chain terminator which has an    isocyanate-reactive group and/or optionally-   E) an organic diisocyanate comprising two isocyanate groups,    where-   F) a catalyst    is optionally used in the first and/or second step,    the molar ratio of the entirety of the isocyanate groups from A) and    optionally E) to the entirety of the isocyanate-reactive groups in    B), C), and optionally D) is ≦0.9:1 and ≦1.2:1

and component B) comprises at least one polyether carbonate polyolobtainable via an addition reaction of carbon dioxide and alkyleneoxides onto H-functional starter substances.

Surprisingly, it has been found that the TPUs produced by the process ofthe invention have good mechanical properties. In particular they arefound to have higher tensile strength and better thermal stability thancorresponding TPUs based on pure C2- or C3-polyether polyols, or elsebased on the polyether carbonate diols known from the prior art. TheTPUs produced in the invention also retain very good elastic propertiesat low temperatures, since no soft-segment crystallization occurs.

For the purposes of the invention, thermoplastic polyurethane elastomersare elastomers which can be processed by a thermoplastic route and Whichcomprise urethane units. These are linear multiphase block copolymerscomposed of what are known as hard and soft segments.

Hard segments are segments formed by the rigid blocks of the copolymer,these being produced by reaction of short-chain chain extenders anddiisocyanates. These blocks have an ordered arrangement, permitted viaphysical interaction with the chain-extender blocks of the adjacentpolymer chain. These interactions provide the modes for the elasticproperties. At the same time, reversible disintegration of these modeson melting is the precondition for the thermoplastic properties.

Reaction of the longer-chain polyol components with diisocyanatesproduces flexible blocks in the copolymer which form the soft segments,which have no ordered arrangement. These are responsible for thechemical properties of the TPU, and also for its low-temperatureflexibility.

In one preferred embodiment of the invention, in the second step theprepolymer is reacted only with

-   C) one or more chain extenders with molar mass ≧60 and ≦490 g/mol,    which have two isocyanate-reactive groups, and optionally-   D) a monofunctional chain terminator which has an    isocyanate-reactive group and/or optionally-   E) an organic diisocyanate comprising two isocyanate groups.

Organic diisocyanates A) that can be used are by way of examplediisocyanates described in Justus Liebigs Anna/en der Chemie, 562, pp.75-136.

Specific mention may be made of the following by way of example:

Aromatic diisocyanates, for example tolylene 2,4-diisocyanate, tolylene2,4-diisocyanateltolylene 2,6-diisocyanate mixtures, diphenylmethane4,4′-diisocyanate, diphenylmethane 2,4′-diisocyanate, anddiphenylmethane 2,2-diisocyanate, diphenylmethane2,4′-diisocyanate/diphenylmethane 4,4′-diisocyanate mixtures,urethane-modified liquid diphenylmethane 4,4′-diisocyanates anddiphenylmethane 2,4′-diisocyanates,4,4′-diisocyanato-1,2-diphenylethane, and naphthylene 1,5-diisocyanate.It is preferable to use, as aromatic organic diisocyanates,diphenylmethane diisocyanate isomer mixtures with >96% by weight contentof diphenylmethane 4,4′-diisocyanate, and in particular diphenylmethane4,4′-diisocyanate and naphthylene 1,5-diisocyanate. The diisocyanatesmentioned can be used individually or in the form of mixtures with oneanother. They can also be used together with up to 15% by weight (basedon the total quantity of diisocyanate) of a polyisocyanate, for exampletriphertylmethane 4,4′,4″-triisocyanate or with polyphenyl polymethylenepolyisocyanates.

Other diisocyanates A) that can be used are aliphatic and cycloaliphaticdiisocyanates. Mention may be made by way of example of hexamethylenediisocyanate, isophorone diisocyanate, cyclohexane 1,4-diisocyanate,1-methylcyclohexane 2,4-diisocyanate, and 1-methylcyclohexane2,6-diisocyanate, and also the corresponding isomer mixtures, anddicyclohexylmethane 4,4′-, 2,4′-, and 2,2′-diisocyanate, and also thecorresponding isomer mixtures. It is preferable that the aliphaticorganic diisocyanate used is composed of at least 50% by weight ofhexamethylene 1,6-diisocyanate, with preference 75% by weight, andparticularly preferably 100% by weight.

In one preferred embodiment of the invention, the organic diisocyanateA) comprises at least one compound selected from the group of aliphatic,aromatic, cycloaliphatic diisocyanates, and particularly preferably atleast one aliphatic and/or one aromatic diisocyanate, very particularlypreferably at least one aromatic diisocyanate.

In the invention, component B) comprises at least one polyethercarbonate polyol obtainable via an addition reaction of carbon dioxideand of alkylene oxides onto H-functional starter substances. For thepurposes of the invention “H-functional” means a starter compound whichhas H atoms that are active in relation to alkoxylation.

The production of polyether carbonate polyols via an addition reactionof alkylene oxides and CO₂ onto H-functional starters is known by way ofexample from EP 0222453 A, WO 2008/013731 A. and EP 2115032 A.

In one preferred embodiment of the invention, the content of carbonategroups, calculated as CO₂ in the polyether carbonate polyol is ≧3 and≦35% by weight, preferably ≧5 and ≦30% by weight, particularlypreferably ≧10 and ≦28% by weight. The determination method is NMR,using the analysis method specified in the section concerningexperimental methods.

In another preferred embodiment of the invention, the number-averagemolar mass M_(n) of the polyether carbonate polyol is ≧500 and ≦10000g/mol, preferably ≧500 and ≦7500 g/mol, particularly preferably ≧750 and≦6000 g/mol and very particularly preferably ≧1000 and ≦5000 g/mol. Thedetermination method is titration of the terminal OH groups, using theanalysis method specified in the section concerning experimental methodsunder OH number determination.

It is preferable that the average OH functionality of the polyethercarbonate polyol is ≧1.85 and ≦2.5, preferably ≧1,9 and ≦2.3,particularly preferably ≧1.95, and ≦2.1 and very particularly preferably≧1.97 and ≦2.03.

Production of the polyether carbonate polyols can generally use alkyleneoxides (epoxides) having from 2 to 24 carbon atoms. Examples of thealkylene oxides having from 2 to 24 carbon atoms are one or morecompounds selected from the group consisting of ethylene oxide,propylene oxide, 1-butene oxide, 2,3-butene oxide, 2-methyl-1,2-propeneoxide (isobutene oxide), 1-pentene oxide, 2,3-pentene oxide,2-methyl-1,2-butene oxide, 3-methyl-1,2-butene oxide, 1-hexene oxide,2,3-hexene oxide, 3,4-hexene oxide, 2-methyl-1,2-pentene oxide,4-methyl-1,2-pentene oxide, 2-ethyl-1,2-butene oxide, 1-heptene oxide,1-octene oxide, 1-nonene oxide, 1-decene oxide, 1-undecene oxide,1-dodecene oxide, 4-methyl-1,2-pentene oxide, butadiene monoxide,isoprene monoxide, cyclopentene oxide, cyclohexene oxide, cyclohepteneoxide, cyclooctene oxide, styrene oxide, methylstyrene oxide, pineneoxide, mono- or polyepoxidized fats in the form of mono-, di-, andtriglyceride, epoxidized fatty acids, C₁-C₂₄-esters of epoxidized fattyacids, epichlorohydrin, glycidol, and derivatives of glycidol, forexample methyl glycidyl ether, ethyl glycidyl ether, 2-ethylhexylglycidyl ether, allyl glycidyl ether, glycidyl methacrylate, and alsoepoxy-functional alkoxysilanes, for example3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane,3- glycidyloxypropyltripropoxysilane,3-glycidyloxypropylmethyldimethoxysilane, 3-glycidyloxypropylethyldiethoxysilane,3-glycidyloxypropyltriisopropoxysilane. It is preferable to use, asalkylene oxides, ethylene oxide and/or propylene oxide, in particularpropylene oxide.

In one particularly preferred embodiment of the invention, theproportion of ethylene oxide in the entire quantity used of the alkyleneoxides is ≧0 and ≦90% by weight, preferably ≧0 and ≦50% by weight,particularly preferably ≧0 and ≦25% by weight.

Compounds having H atoms that are active in relation to alkoxylation canbe used as suitable H-functional starter substance. Examples of groupsthat are active in relation to alkoxylation, having active H atoms, are—OH, —NH₂ (primary amines), —NH— (secondary amines), —SH, and —CO₂H.Preference is given to —OH and —NH₂, particularly preference being givento —OH. By way of example, one or more compounds selected from the groupconsisting of polyhydric alcohols, polyfunctional amines, polyfunctionalthiols, amino alcohols, thio alcohols, hydroxyesters, polyether polyols,polyester polyols, polyester ether polyols, polyether carbonate polyols,polycarbonate polyols, polycarbonates, polyethyleneimines, polyetheramines (e.g. those known as Jeffamine® from Huntsman),polytetrahydrofurans (e.g. PolyTHF® from BASF, e.g. PolyTHF® 250, 650S,1000, 1000S, 1400, 1800, 2000), polytetrahydrofuranamines (BASF productpolytetrahydrofuranamine 1700), polyether thiols, polyacrylate polyols,castor oil, the mono- or diglyceride of ricinoleic acid, monoglyceridesof fatty acids, chemically modified mono-, di- and/or triglycerides offatty acids, and C₁-C₂₄ alkyl fatty acid esters, where these comprise anaverage of at least two OH groups per molecule, can be used asH-functional starter substance, The C₁-C₄ alkyl fatty acid esters, wherethese comprise an average of at least two OH groups per molecule, are byway of example commercially available products such as Lupranol Balance®(BASE AG), Merginol® grades (Hobum Oleochemicals GmbH), Sovermol® grades(Cognis Deutschland GmbH & Co. KG), and Soyol® grades (USSC Co.).

Examples of polyhydric alcohols suitable as H-functional startersubstances are dihydric alcohols, e.g. ethylene glycol, diethyleneglycol, propylene glycol, dipropylene glycol, 1,3-propanediol,1,4-butanediol, 1,4-butenediol, 1,4-butynediol, neopentyl glycol,1,5-pentanediol, methylpentanediol (e.g. 3-methyl-1,5-pentanediol),1.,6-hexanediol; 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol,bis(hydroxymethyl)cyclohexanes (e.g. 1,4-bis(hydroxymethyl)cyclohexane),triethylene glycol, tetraethylene glycol, polyethylene glycol,dipropylene glycol, tripropylene glycol, polypropylene glycol,dibutylene glycol, and polybutylene glycols, and also all of themodification products of these abovementioned alcohols with variousquantities of ε-caprolactone. Mixtures of H-functional starters can alsouse trihydric alcohols, for example trimethylolpropane, glycerol,trishydroxyethyl isocyanurate, and castor oil.

The H-functional starter substances can also be selected from thepolyether polyols substance class, in particular those with anumber-average molar mass M_(n), in the range from 200 to 4000 g/mol,preferably from 250 to 2000 g/mol, Preference is given to polyetherpolyols composed of repeating units of ethylene oxide and of propyleneoxide, preferably having a proportion of from 35 to 100% of propyleneoxide units, particularly preferably having a proportion of from 50 to100% of propylene oxide units. These can be random copolymers, gradientcopolymers, or alternating or block copolymers of ethylene oxide andpropylene oxide. Examples of suitable polyether polyols composed ofrepeating units of propylene oxide and/or of ethylene oxide are theDesmophen®-, Acclaim®-, Arcol®-, Baycoll®-, Bayfill®-, Bayflex®-,Baygal®-, PET®, and polyether polyols from Bayer MaterialScience AG(e.g. Desmophen® 3600Z, Desmophen® 1900U, Acclaim® Polyol 2200, Acclaim®Polyol 40001, Arcol® Polyol 1004, Arcol® Polyol 1010, Arcol® Polyol1030, Arcol® Polyol 1070, Baycoll® BD 1110, Bayfill® VPPU 0789, Baygal®K55, PET® 1004, Polyether® S180). Examples of other suitablehomopolyethylene oxides are the Pluriol® E grades from BASF SE, andexamples of suitable homopolypropylene oxides are the Pluriol® P gradesfrom BASF SE, and examples of suitable mixed copolymers of ethyleneoxide and propylene oxide are the Pluronic® PE or Pluriol® RPE gradesfrom BASF SE.

The H-functional starter substances can also be selected from thepolyester polyols substance class, in particular those with anumber-average molar mass M_(n) in the range from 200 to 4500 g/mol,preferably from 400 to 2500 g/mol. Polyester polyols used comprise atleast difunctional polyesters. Polyester polyols are preferably composedof alternating acid units and alcohol units. Examples of acid componentsused are succinic acid, maleic acid, maleic anhydride, adipic acid,phthalic anhydride, phthalic acid, isophthalic acid, terephthalic acid,tetrahydrophthalic acid, tetrahydrophthalic anhydride, hexahydrophthalicanhydride, and mixtures of the acids and/or anhydrides mentioned.Examples of alcohol components used are 1,2-ethanediol, 1,2-propanediol,1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol,1,6-hexanediol, 1,4-bis(hydroxymethyl)cyclohexane, diethylene glycol,dipropylene glycol, trimethylolpropane, glycerol, and mixtures of thealcohols mentioned. If dihydric or polyhydric polyether polyols are usedas alcohol component, polyester ether polyols are thus obtained and canlikewise serve as starter substances for the production of the polyethercarbonate polyols. If polyether polyols are used for the production ofthe polyester ether polyols, preference is given to polyether polyolswith a number-average molar mass M_(n) of from 150 to 2000 g/mol.

Other H-functional starter substances that can be used are polycarbonatepolyols, for example polycarbonate diols, in particular those with anumber-average molar mass M_(n) in the range from 150 to 4500 g/mol,preferably from 500 to 2500 g/mol, these being produced by way ofexample via reaction of phosgene, dimethyl carbonate, diethyl carbonate,or diphenyl carbonate and di- and/or polyhydric alcohols, or polyesterpolyols, or polyether polyols. Examples of polycarbonate polyols arefound by way of example in EP 1359177 A. Poly-carbonate diols used canby way of example comprise the Desmophen® C grades from BayerMaterialScience AG, e.g. Desmophen® C 1100 or Desmophen® C 2200.

Polyether carbonate polyols can likewise be used as H-functional startersubstances. In particular, polyether carbonate polyols produced by theprocess described here are used. These polyether carbonate polyols usedas H-functional starter substances are produced in advance for thispurpose in a separate reaction step.

The functionality (i.e. number of H atoms per molecule that are activein relation to polymerization) of the H-functional starter substances isgenerally from 1. to 4, preferably 2 or 3, and particularly preferably2. The H-functional starter substances are used either individually orin the firm of mixture of at least two H-functional starter substances.

Preferred H-functional starter substances are alcohols of the generalformula (I),

HO—(CH₂)_(x)—OH   (I)

where x is a number from 1 to 20, preferably an even number from 2 to20. Examples of alcohols of formula (I) are ethylene glycol,1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, and1,12-dodecanediol. Other preferred H-functional starter substances areneopentyl glycol, trimethylolpropane glycerol, pentaerythritol, reactionproducts of the alcohols of formula (I) with ε-caprolactone, e.g.reaction products of trimethylolpropane with ε-caprolactone, reactionproducts of glycerol with ε-caprolactone, and also reaction products ofpentaerythritol with ε-caprolactone. Preference is further given to thefollowing H-functional starter substances: water, diethylene glycol,dipropylene glycol, castor oil, sorbitol, and polyether polyols composedof repeating units of polyalkylene oxides.

It is particularly preferable that the H-functional starter substancesare one or more compounds selected from the group consisting of ethyleneglycol, propylene glycol, 1,3-propanediol, 1,3-butanediol,1,4-butanediol, 1,5-pentanediol, 2-methylpropane-1,3-diol, neopentylglycol, 1,6-hexanediol diethylene glycol, dipropylene glycol, glycerol,trimethylolpropane, di- and trihydric polyether polyols, where thepolyether polyol is composed of a di- or tri-H-functional startersubstance and propylene oxide or of a di or tri-H-functional startersubstance, propylene oxide, and ethylene oxide. The number-average molarmass M_(n) of the polyether polyols is preferably in the range from 62to 4500 g/mol, and in particular in the range from 62 to 3000 g/mol,very particularly preferably from 62 to 1500 g/mol. The functionality ofthe polyether polyols is preferably from 2 to 3, particularly preferably2.

In one preferred embodiment of the invention, the polyether carbonatepolyol is obtainable via an addition reaction of carbon dioxide and ofalkylene oxides onto H-functional starter substances with the use ofmultimetal cyanide catalysts (DMC catalysts). The production ofpolyether carbonate polyols via an addition reaction of alkylene oxidesand CO₂ onto H-functional starters with the use of DMC catalysts isdisclosed by way of example in EP 0222453 A. WO 2008/013731 A. arid EP21150:32 A.

DMC catalysts are in principle known from the prior art relating to thehomopolymerization of epoxides (see for example U.S. Pat. No. 3,404,109A, U.S. Pat. No. 3,829,505 A, U.S. Pat. No. 3,941,849 A, and U.S. Pat.No. 5,158,922 A). DMC catalysts described by way of example in U.S. Pat.No. 5,470,813 A, EP 700 949 A, EP 743 093 A, EP 761 708 A, WO 97/40086A, WO 98/16310 A and WO 00/47649 A have very high activity in thehomopolymerization of epoxides, and permit the production of polyetherpolyols at very low catalyst concentrations (25 ppm or less), Thehigh-activity DMC catalysts described in EP-A 700 949 are a typicalexample, and comprise not only a double metal cyanide compound (e.g.zinc hexacyanocobaltate(III)) and an organic ligand (e.g. tert-butanol),but also a polyether with a number-average molar mass M_(n) greater than500 g/mol.

The quantity used of the DMC catalyst is mostly smaller than 1% byweight, preferably smaller than 0.5% by weight, particularly preferablysmaller than 500 ppm, and in particular smaller than 300 ppm, based ineach case on the weight of the polyether carbonate polyol.

The polyether carbonate polyols are preferably produced in a pressurereactor. One or more alkylene oxides, and the carbon dioxide, aremetered into the system after the optional drying of a starter substanceor of the mixture of a plurality of starter substances, and the additionof the DMC catalyst, and also of the additive(s), these being added inthe form of solid or in the form of a suspension before or after thedrying process. In principle, various methods can be used for themetering of one or more alkylene oxides and of the carbon dioxide intothe system. The metering can be started in vacuo or at a preselectedadmission pressure. It is preferable to set the admission pressure viaintroduction of an inert gas, for example nitrogen, where the pressureset is from 10 mbar to 5 bar, preferably from 100 mbar to 3 bar, andwith preference from 500 mbar to 2 bar.

The metering of one or more alkylene oxides and of the carbon dioxideinto the system can take place simultaneously or sequentially, and theentire quantity of carbon dioxide here can be added all at once ormetered into the system during the reaction time. Preference is given tometering of the carbon dioxide into the system. One or more alkyleneoxides is/are metered into the system simultaneously or sequentially inrelation to the metering of the carbon dioxide into the system. if aplurality of alkylene oxides are used for the synthesis of the polyethercarbonate polyols, these can be metered into the system simultaneouslyor sequentially by way of respective separate feeds, or by way of one ormore feeds where at least two alkylene oxides are metered in the form ofmixture into the system. It is possible to synthesize random,alternating, block-type, or gradient-type polyether carbonate polyols byvarying the way in which the alkylene oxides and the carbon dioxide aremetered into the system.

It is preferable to use an excess of carbon dioxide, and in particularthe quantity of carbon dioxide is determined by way of the totalpressure under reaction conditions. An excess of carbon dioxide isadvantageous because carbon dioxide is unreactive. The reaction has beenfound to produce the polyether carbonate polyols at from 60 to 150° C.,preferably from 70 to 140° C., particularly preferably from 80 to 130°C., and at pressures of from 0 to 100 bar, preferably from 1 to 90 bar,and particularly preferably from 3 to 80 bar. At temperatures below 60°C., the reaction ceases. At temperatures above 150° C., the quantity ofundesired by-products increases sharply.

The proportion of polyether carbonate polyols, based on the total massof component B), is preferably ≧5 and ≦100% by weight, particularlypreferably ≧10 and ≦100% by weight, and very particularly preferably ≧20and ≦100% by weight. It is also possible that various polyethercarbonate polyols are present in component B).

It is also possible to use, as component B), mixtures of theabovementioned polyether carbonate polyols with other linearhydroxyl-terminated polyols with a number-average molar mass M_(n) offrom 500 to 5000 g/mol, preferably from 750 to 4000 g/mol, andparticularly preferably from 1000 to 3000 g/mol. By virtue of theproduction process, these other polyols often comprise small quantitiesof nonlinear compounds. An expression therefore often used is“essentially linear polyols”. Preferred other polyols are polyesterdiols, polyether diols, polycarbonate diols, and mixtures of these.

Suitable polyether diols can thus be produced by reacting one or morealkylene oxides having from 2 to 4 carbon atoms in the alkylene moietywith a starter molecule which comprises two active hydrogen atoms.Examples that may be mentioned of alkylene oxides are: ethylene oxide,1,2-propylene oxide, epichlorohydrin, and 1,2-butylene oxide, and2,3-butylene oxide, It is preferable to use ethylene oxide, propyleneoxide, and mixtures of 1,2-propylene oxide and ethylene oxide. Thealkylene oxides can be used individually, in alternating succession, orin the form of mixtures. Examples of starter molecules that can be usedare: water, amino alcohols, for example N-alkyldiethanolamines, forexample N-methyldiethanolamine, and diols, for example ethylene glycol,1,3-propylene glycol, 1,4-butanediol, and 1,6-hexanediol. Mixtures ofstarter molecules can optionally also be used. Other suitable polyetherdiols are the tetrahydrofuran polymerization products containinghydroxyl groups. It is also possible to use proportions of from 0 to30%, based on the bifunctional polyethers, of trifunctional polyethers,the quantity of these being however at most that which produces athermoplastically processible product. The average molar masses M_(n) ofsuitable polyether diols is from 500 to 6000 g/mol, preferably from 750to 4000 g/mol, and very particularly preferably from 1000 to 3000 g/mol.They can be used either individually or else in the form of mixtureswith one another.

Suitable polyester diols can by way of example be produced fromdicarboxylic acids having from 2 to 12 carbon atoms, preferably havingfrom 4 to 6 carbon atoms, and from polyhydric alcohols. Examples ofdicarboxylic acids that can be used are: aliphatic dicarboxylic acids,for example succinic acid, maleic acid, glutaric acid, adipic acid,suberic acid, azelaic acid, and sebacic acid, and aromatic dicarboxylicacids, for example phthalic acid, isophthalic acid, and terephthalicacid. The dicarboxylic acids can be used individually or in the form ofmixtures, e.g. in the form of a succinic, glutaric, and adipic acidmixture. For the production of the polyester diols it can optionally beadvantageous to use, instead of the dicarboxylic acids, thecorresponding dicarboxylic acid derivatives, for example carboxylicdiesters having from 1 to 4 carbon atoms in the alcohol moiety,carboxylic anhydrides, or acyl chlorides. Examples of polyhydricalcohols are glycols having from 2 to 10, preferably from 2 to 6, carbonatoms, for example ethylene glycol, diethylene glycol, 1,4-butanediol,1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, 1,12-dodecanediol,2,2-dimethyl-1,3-propanediol, 1,3-propanediol, and dipropylene glycol.The polyhydric alcohols can be used alone or optionally in a mixturewith one another, as required by the desired properties. Other suitablecompounds are esters of carbonic acid with the diols mentioned, inparticular those having from 4 to 6 carbon atoms, for example1,4-butanediol or 1,6-hexanediol condensates of hydroxycarboxylic acids,for example hydroxycaproic acid, and polymerization products oflactones, for example optionally substituted caprolactones. Preferredpolyester diols used are ethanediol polyadipates,1,4-butanediolpolyadipates, ethanediol 1,4-butanediol polyadipates,1,6-hexanediol neopentyl glycol polyadipates, 1,6-hexanediol1,4-butanediol polyadipates, and polycaprolactones. The number-averagemolar mass M_(n) of the polyester diols is from 500 to 5000 g/mol,preferably from 600 to 4000 g/mol, and particularly preferably from 800to 3000 g/mol, and they can be used individually or in the form ofmixtures with one another.

Chain extenders C) used can comprise tow-molecular-weight compounds witha molar mass of ≧60 and ≦490 g/mol, preferably ≧62 and ≦400 g/mol, andparticularly preferably ≧62 and ≦300 g/mol, where these have twoisocyanate-reactive groups.

In one preferred embodiment of the invention, the chain extenders C)comprise, or consist of, diols, diamines, or diol/diamine mixtures,however preferably diols.

Suitable chain extenders are diols such as ethanediol, 1,3-propanediol,1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol,1,10-decanediol, 1,12-dodecanediol, diethylene glycol, dipropyleneglycol, neopentyl glycol, diesters of terephthalic acid with glycolshaving from 2 to 4 carbon atoms, for example bis(ethylene glycol)terephthlate or bis(1,4-butanediol) terephthlate, hydroxyalkylene ethersof hydroquinone, for example 1,4-di(hydroxyethyl)hydroquinone, andethoxylated bisphenols, and also reaction products of these withε-caprolactone.

Preferred chains extenders are aliphatic diols having from 2 to 14carbon atoms, for example ethanediol, 1.,3-propanediol, 1,4-butanediol,1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol,1,12-dodecanediol, diethylene glycol, dipropylene glycol, neopentylglycol, and 1 ,4-di(hydroxyethyl)hydroquinone. Particular preference isgiven to the use of 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, and1,4-di(hydroxyethyl)hydroquinone as chain extender.

Other suitable chain extenders are (cyclo)aliphatic diamines, forexample isophoronediamine, ethylenediamine, 1,2-propylenediamine,1,3-propylenediamine, N-methylpropylene-1,3-diamine,N,N′-dimethylethylenediamine, and aromatic diamines, for example2,4-tolylenediamine and 2,6-tolylenediamine,3,5-diethyl-2,4-tolylenediamine, and 3,5-diethyl-2,6-tolylenediamine,and primary mono-, di-, tri-, or tetraalkyl-substituted 4,4°-diaminodiphenylmethanes.

Chain terminators D) that can be used are low-molecular-weight compoundshaving an isocyanate-reactive group, for example monoalcohols ormonoamines. It is preferable to use at least one compound selected fromthe group of 1-octanol, stearyl alcohol, 1-butylamine, and stearylamine,and it is particularly preferable to use 1-octanol.

Compounds suitable as other organic dilsocyanates E) are any of thecompounds mentioned for component A).

The TPUs can be produced by reacting quantities of the structuralcomponents such that the molar ratio of the entirety of the isocyanategroups from A) and optionally E) to the entirety of the groups in B),C), and optionally D) reactive toward isocyanate is from 0.9:1 to 1.2:1,preferably from 0.92:1 to 1.15:1, and particularly preferably from 0.94to 1.10:1.

The Shore hardness of the TPUs produced via the processes of theinvention can be varied widely, for example from Shore A 45 to Shore D90, via adjustment of the molar ratio of polyol B) to chain extender C).

Suitable catalysts F) can optionally be used in the first and/or secondstep of the process of the invention. The conventional tertiary aminesknown from the prior art, e.g. triethylamine, dimethylcyclohexylamine,N-methylmorpholine, N,N′-dimethylpiperazine,2-(dimethylaminoethoxy)ethanol, diazabicyclo[2.2.2]octane, and alsoorganometallic compounds, for example titanium compounds, ironcompounds, or tin compounds, for example tin diacetate, tin dioctanoate,tin dilaurate, or the dialkyltin salts of aliphatic carboxylic acids,for example dibutyltin diacetate or dibutyltin dilaurate, are suitablecatalysts for the production of TPUs. Preferred catalysts areorganometallic compounds, in particular titanium compounds or ironcompounds or tin compounds.

The total quantity of catalysts in the TPUs is generally about 0 to 5%by weight, preferably from 0.0001 to 1% by weight, and particularlypreferably from 0.0002 to 0.5% by weight.

It is moreover also possible to add auxiliaries and/or additionalsubstances during any of the steps of the process of the invention.Mention may be made by way of example of lubricants, for example tattyacid esters, metal soaps of these, fatty acid amides, fatty acid esteramides, and silicone compounds, antiblocking agents, inhibitors,stabilizers with respect to hydrolysis, UV or other light, heat, anddiscoloration, flame retardants, dyes, pigments, inorganic and/ororganic fillers, and reinforcing agents. Reinforcing agents are inparticular fibrous reinforcing materials, e.g. inorganic fibers, wherethese are produced in accordance with the prior art and can also havebeen treated with a size. Information in greater detail concerning theauxiliaries and additional substances mentioned can be found in thetechnical literature, for example in the monograph by J. H. Saunders andK. C. Frisch “High Polymers”, volume XVI, Polyurethane, Parts 1 and 2,Verlag Interscience Publishers 1962 and 1964, and Taschenbuch fürKunststoff-Additive [Plastics additives handbook] by R. Gächter and HMüller (Hanser Verlag Munich 1990), or DE 29 01 774 A.

Other additions that can be incorporated into the TPUs arethermoplastics, for example polycarbonates andacrylonitrile/butadiene/styrene terpolymers (ABS). It is also possibleto use other elastomers, for example rubber, ethylene/vinyl acetatecopolymers, styrene/butadiene copolymers, and also other TPUs. Othercompounds suitable for incorporation are commercially availableplasticizers, for example phosphates, phthalates, adipates, sebacates,and alkylsulfonates.

For the production of the thermoplastic polyurethane in the process ofthe invention, components A) and B) can preferably be reacted in a firststep, optionally in the presence of catalysts F), at a temperature thatis preferably from 100 to 250° C., particularly preferably from 100 to220° C., to give an NCO-terminated prepolymer.

Selection of the quantities of the reaction components for the formationof prepolymer in the first step is preferably such that the molar ratioof the isocyanate groups from A) to the groups in B) reactive towardisocyanate is from 1.1:1 to 5:1, particularly from 1.1:1 to 4:1, andparticularly from 1.1:1 to 3.5:1.

It is preferable here that the components are mixed intimately with oneanother, and that the prepolymer reaction is preferably in essencecarried out to full conversion, based on the polyol component. Fullconversion can be checked via titration of the NCO content.

In a second step in the invention, the NCO-terminated prepolymer is thenreacted with the components C) chain extender and optionally D) chainterminator, and E) other organic diisocyanate, optionally in thepresence of F) catalysts. In one preferred embodiment of the invention,the NCO-terminated prepolymer is then reacted only with the componentsC) chain extender and optionally D) chain terminator, and E) otherorganic diisocyanate, optionally in the presence of F) catalysts.

It is preferable here that the reaction temperatures selected are thesame as those for the production of the prepolymer. However, it is alsopossible to select the reaction temperatures and reaction times freely,as required by the reactivity of the chain extender. It is preferable tocontinue the reaction until the maximum possible stirrer torque isreached, and the reaction melt can then preferably be poured onto ametal sheet and then conditioned for a certain time, for example from 30to 120 minutes, with a certain temperature range, from example from 80to 120° C. After the resultant TPU sheets have cooled, they can bechopped and granulated. The resultant granulated TPU material can thenbe processed by thermoplastic route, e.g. in an injection-moldingmachine.

The TPUs can be produced either batchwise or continuously. Thebest-known industrial production processes used for this purpose are themixing-head-belt process (GB 1 057 018 A) and the extruder process (DE 1964 834 A, DE 2 059 570 A, and U.S. Pat. No. 5,795,948 A).

The known mixing assemblies are suitable for the process of theinvention for the production of TPU, preference being given to thoseoperating with high shear energy. For the continuous production processmention may be made by way of example of co-kneaders, preferablyextruders, for example twin-screw extruders and Buss kneaders.

In one preferred embodiment of the invention, the reaction of thecomponents takes place in a reactive extruder or by the mixing-head-beltprocess.

The process of the invention can by way of example be carried out in atwin-screw extruder by producing the prepolymer in the first part of theextruder and then adding the chain extenders C), and also optionallycomponents D) and E), in the second part. It is possible here to add thechain extender in parallel with components D) and E) into the samemetering aperture of the extruder, or preferably to add these insuccession into separate apertures. It is also possible that variouschain extenders C) are metered into the system in the form of a mixture,in parallel or at separate metering apertures.

However, it is also possible to produce the prepolymer outside of theextruder in a separate, upstream prepolymer reactor, batchwise in a tankor continuously in a tube with static mixers, or in a stirred tube(tubular mixer).

However, it is also possible to use a mixing apparatus, e.g. a staticmixer, to mix the chain extender and optionally components D) and E)with a prepolymer produced in a separate prepolymer reactor. Thisreaction mixture is then preferably, by analogy of the known beltprocess, applied continuously to a support, preferably a conveyor belt,where it is allowed to react until the material solidifies to give theTPU, optionally with heating of the belt.

The invention further provides a thermoplastic polyurethane elastomerobtainable by the process described above of the invention.

The invention further provides the use of the thermoplastic polyurethaneelastomers produced by the process of the invention for the productionof injection-molded or extruded items, and also the actual items thatare objects of the invention produced via injection molding orextrusion.

The parts produced from the TPUs of the invention harden rapidly whenprocessed by injection molding, and therefore have good demoldability.The injection-molded parts have high dimensional stability and are veryheat-resistant.

The TPUs of the invention can be used for the production of a very widevariety of useful parts appropriate to their level of hardness, forexample for the production of soft, flexible injection-molded parts, forexample shoe soles, grip recesses, sealing parts, and dust caps, andalso for harder parts, for example rollers, conveyor belts, ski boots,etc. Combination with other thermoplastics gives products withattractive grip feel (hard-soft combination).

The materials can also be used to produce extruded items, e.g. profiles,films, foils, and hoses.

The examples below will provide further explanation of the invention:

EXAMPLES

The following methods were used to characterize the polymeric polyolsused:

The CO₂ content incorporated within the polyether carbonate polyols wasdetermined by means of ¹NMR (Bruker, DPX 400, 400 MHz; pulse programzg30, delay d1: 5 s, 100 scans). In each case the sample was dissolvedin deuterated chloroform. Internal standard added to the deuteratedsolvent comprised dimethyl terephthalate (2 mg for every 2 g of CDCl₃).The relevant resonances in the ¹H NMR (based on CHCl₃=7.24 ppm) are asfollows:

Carbonates, resulting from carbon dioxide incorporated within thepolyether carbonate polyol (resonances at from 5.2 to 4.8 ppm) PO notconsumed in the reaction with resonance at 2.4 ppm, polyether polyol(i.e. without incorporated carbon dioxide) with resonances at from 1.2to 1.0 ppm.

The molar content of the carbonate incorporated within the polymer, ofthe polyether polyol fractions, and also of the PO not consumed in thereaction are determined via integration of the corresponding signals.

All of the number-average molar masses M_(n) stated in the descriptionand in the examples for the polymeric polyols were determined asfollows: the OH number was first determined experimentally viaesterification followed by back-titration of the excess esterificationreagent with standard alcoholic potassium hydroxide solution inaccordance with DIN 53240-2. The OH number is stated in mg KOH per gramof polyol. The number-average molar mass can be calculated from the OHnumber by way of the following formula: number-average molar massM=56×1000×OH functionality/OH number. The present examples assume OHfunctionality F to be approximately 2.0.

In the case of low-molecular-weight polyols with defined structure, themolar mass is calculated from the molecular formula.

Production of TPUs 1 to 7 Stage 1)

The appropriate polyol (at 190° C.) and the diphenylmethane4,4′-diisocyanate (MDI) at 60° C. were reacted, with stirring, as intable 1 in a reaction vessel. In all of the examples 1 to 18 thereaction was catalyzed with 20 ppm (based on the polyol) of Tyzor® AA105 (Dorf Ketal) (except in the case of examples 17 and 18; these used50 ppm of Desmorapid®SO from Bayer Material Science AG, Leverkusen(tin(11) 2-ethylhexanoate)). In all of the experiments, concomitant usewas also made of 1% of Licowax® C (Clariant) as mold-release agent(except in the case of examples 17 and 18; these used 0.3% by weight ofLoxiol®3324 from Emery Oleochemicals, Düsseldorf) and 0.3% by weight ofIrganox® 1010 (BASF SE) as antioxidant. The reaction mixture reached atemperature maximum (prepolymer formation). After about 60 sec. ofreaction time, the procedure was continued with stage 2. Operations inexamples 19 to 21 were analogous to those of example 17, but withoutcatalyst and additionally with 0.045% by weight of Wacker®AK1000silicone oil from Wacker Chemie AG and 0.185% by weight ofTinuvin®PUR866 from BASF SE.

Stage 2)

The 1,4-butanediol, heated to 60° C., was added in one portion to theprepolymer mixture of stage 1, and incorporated by mixing with vigorousstirring. After about 10 to 15 seconds, the reaction mixture was pouredonto a coated metal sheet and subjected to postconditioning at 80° C.for 30 minutes, After cooling, this gave a cast TPU sheet.

Production of TPU 8 with the Molar Data of Table 1

Stages 1 and 2

A prepolymer was produced from polyol No. 2 and MDI as in examples 1 to7. The resultant prepolymer was then further reacted with polyol No. 1and 1,4-butanediol. The reaction mixture was poured onto a coated metalsheet and subjected to postconditioning at 80° C. for 30 minutes. Aftercooling, this gave a cast TPU sheet.

Table 1 describes the components used, and proportions thereof, for theproduction of the TPUs.

TABLE 1 Molar proportions of the starting components for the synthesisof the TPUs Polyol MDI 1,4-Butanediol Example Polyol No. [mol] [mol][mol] 1* 1 1 4 3 2  2 1 4 3 3* 3 1 4 3 4  4 1 6.6 5.6 5* 5 1 6.6 5.6 6*1 and 5 0.5 + 0.5 5.3 4.3 7  6 1 5.3 4.3 8  2 and 1 0.67 + 0.33 4 3*comparative example not of the invention

Polyol 1: Acclaim®2200 (polypropylene oxide glycol with OH number 56.7mg KOH/g (M_(n)=1979 g/mol, from Bayer MaterialScience AG).

Polyol 2: Polyether carbonate diol based on propylene oxide and CO₂ withOH number 58.2 mg KOH/g (M_(n)=1928 g/mol) and with 15.1% by weightincorporated CO₂ content.

Polyol 3: Polyether carbonate diol with OH number 60.9 mg KOH/g(M_(n)=1842 g/mol) obtained via reaction of a polypropylene oxide glycolwith OH number 522 mg KOH/g with diphenyl carbonate with elimination ofphenol.

Polyol 4: Polyether carbonate diol based on propylene oxide and CO₂ withOH number 28.5 mg KOH/g (M_(n)=3937 g/mol) and with 19.0% by weightincorporated CO₂ content.

Polyol 5: Acclaim®4200 (polypropylene oxide glycol with OH number 28.9mg KOH/g (M_(n)=3882 g/mol, from Bayer MaterialScience AG).

Polyol 6: Polyether carbonate diol based on propylene oxide and CO₂ withOH number 37.7 mg KOH/g (M_(n)=2976 g/mol) and with 17.5% by weightincorporated CO₂ content.

Studies on TPUs 1 to 8:

The resultant cast TPU sheets were chopped and granulated. Thegranulated material was processed in an Arburg Allrounder 470Sinjection-molding machine in a temperature range from 180 to 230° C. andin a pressure range from 650 to 750 bar with an injection flow rate offrom 10 to 35 cm³/s to give bars (mold temperature: 40° C.; bar size:80×10×4 mm) and sheets (mold temperature: 40° C.; size: 125×50×2 mm).

The following test methods were used:

Hardness was measured in accordance with DIN 53505, abrasion wasmeasured in accordance with DIN ISO 4649-A, and the tensile test wascarried out in accordance with ISO 37.

Dynamic mechanical analysis (DMA: storage-tensile modulus ofelasticity):

Rectangles (30 mm×10 mm×2 mm) were punched out from the injection-moldedsheets. These test sheets, under constant preload—where appropriatedependent on the storage modulus—were subjected to periodic excitationwith very small deformations, and the force acting on the clamp systemwas measured as a function of the temperature and excitation frequency.

The preload additionally applied serves to retain adequate clamping ofthe sample when deformation amplitude is negative.

The DMA measurements were taken using a Seiko DMS 210 at 1 Hz in thetemperature range from −150° C. to 200° C. with a heating rate of 2°C./min.

The behavior of the invention under warm conditions was characterized bymeasuring and stating the storage-tensile modulus of elasticity at +20°C. and at +60° C., for comparison.

Heat resistance is characterized by stating the temperature at which thevalue is less than 2 MPa, i.e. the injection-molded part no longerretains a stable shape. The higher the temperature value, the morestable the TPU.

Table 2 describes the properties determined for the TPUs 1 to 8.

TABLE 2 Results Example 1* 2 3* 4 5* 6* 7 8 Immediate hardness [Shore A]83 85 90 75 64 74 82 86 Abrasion [mm³] 83 38 132 207 249 180 139 71 100%modulus [MPa] 6.4 9.7 11.9 4.9 3.0 4.3 7.0 7.8 300% modulus [MPa] 10.315.9 14.7 7.9 5.5 7.5 11.3 12.3 Tensile strength [MPa] 22.2 32.2 16.910.4 8.0 12.6 19.3 24.1 Tensile strain value [%] 651 553 496 775 793 857649 596 DMA measurement: Modulus of elasticity (20° C.) [MPa] 26 120 5118 6 10 32 33 Modulus of elasticity (60° C.) [MPa] 17 31 18 10 5 9 16 18T (2 MPa) [° C.] 139.3 145.3 137.2 119.8 110.8 120.1 136.8 143*comparative example not of the invention

When the TPUs of the invention from examples 2 and 8 are compared withthe respective examples (1 and 3) not of the invention, they havesimilarly high hardness by virtue of the identical molar quantity ofchain extender and therefore hard segments. The TPUs of the inventionfrom examples 2 and 8 moreover have a markedly better level ofmechanical properties than the respective comparative products (examples1 and 3), this being particularly apparent from the tensile strength.The abrasion values of the TPUs of the invention from examples 2 and 8are likewise markedly lower than the abrasion values of the comparativeTPUs.

The two other TPUs of the invention from examples 4 and 7 also have abetter level of mechanical properties and better abrasion values thanthe respective comparative examples 5 and 6.

The modulus of elasticity value measured by DMA at ±20° C. and at +60°C. are markedly higher for examples 2, 4, 7, and 8 of the invention thanfor the corresponding comparative examples 1, 3, 5, and 6, as also isthe temperature at which a minimum stress of 2 MPa is retained. At hightemperatures, the TPUs of the invention are therefore markedly moreheat-resistant than the comparative TPUs.

Table 3 below describes the components used, and proportions thereof,for the production of TPU 9 to TPU 21.

TABLE 3 Molar proportions of the starting components for the synthesisof the TPUs Polyol MDI 1,4-Butanediol Example Polyol No. [mol] [mol][mol]  9* 1 1 4.08 3 10 7 1 4.08 3 11 8 1 4.08 3 12 1 and 7 0.1 + 0.94.08 3 13 1 and 7 0.25 + 0.75 4.08 3 14 1 and 7 0.5 + 0.5 4.08 3 15 1and 7 0.75 + 0.25 4.08 3 16 1 and 7 0.9 + 0.1 4.08 3  17* 9 1 2.35 1.318  9 and 11 0.67 + 0.33 2.35 1.3  19*  9 and 10 0.67 + 0.33 7.36 6.2220 11 and 10 0.67 + 0.33 7.36 6.22 21 9 and 7 0.67 + 0.33 7.36 6.22*comparative example not of the invention

Polyol 7: Polyether carbonate diol based on 1,2-propanediol, propyleneoxide and CO₂ with OH number 55.5 mg KOH/g (M_(n)=2022 g/mol) and with18.8% by weight incorporated CO₂ content.

Polyol 8: Polyether carbonate diol based on 1,2-propanediol, propyleneoxide and CO₂ with OH number 59.8 mg KOH/g (M_(n)=1876 g/mol) and with24.7% by weight incorporated CO₂ content.

Polyol 9: Terathane® 1000, polytetramethylene glycol from Invista withOH number 114,4 mg KOH/g, (M_(n)=981 g/mol).

Polyol 10: Terathane® 2000, polytetramethylene glycol from Invista withOH number 55.0 mg KOH/g (M_(n)=2040 g/mol).

Polyol 11: Polyether carbonate diol based on 1,2-propanediol, propyleneoxide and CO₂ with OH number 115.5 mg KOH/g (M_(n)=971 g/mol) and with15.4% by weight incorporated CO₂ content.

The TPUs produced from examples 9 to 21 were processed as describedabove examples 1 to 8), and the mechanical properties were determined.The values found are listed in table 4 below.

TABLE 4 Results of examples 9 to 21 TPU Tensile from Hardness 100% 300%Tensile strain example [Shore modulus modulus strength value No. A/D][MPa] [MPa] [MPa] [%]  9* 83A 5.0 8.4 16.8 729 10 88A 10.4 17.3 35.5 58311 94A 16.0 24.1 34.2 506 12 82A 8.3 14.6 31.0 586 13 84A 7.7 13.4 32.4610 14 83A 6.6 11.7 27.8 621 15 84A 6.5 11.5 27.4 623 16 84A 6.2 11.228.1 625  17* 86A 7.4 15.9 38.2 417 18 85A 7.6 14.7 38.8 474  19* 66D31.1 — 36.2 219 20 72D 35.6 44.8 45.3 308 21 69D 32.5 41.6 41.6 310*comparative example not of the invention

When the TPUs of the invention from examples 10 and 11 are compared withthe comparative TPU from example 9, they have higher hardness andmarkedly higher mechanical strength values (modulus values and tensilestrength). Although the tensile strain value is somewhat smaller thanfor the TPU from example 9, it remains very good: above 500%.

When the TPUs of the invention from examples 12 to 16 are compared withthe comparative TPU from example 9 they have similarly high hardness,but a markedly higher level in mechanical properties (modulus values andtensile strength) with very good tensile strain value, although thequantity of polyether carbonate diol used concomitantly in test 16 wasonly 10 mol %.

When the TPUs of the invention from example 18 is compared with thecomparative TPU from example 17 it has comparable hardness and an almostidentical level of mechanical properties, but the tensile strain valueof the TPU of the invention is markedly better.

When the TPUs of the invention from examples 20 and 21 are compared withthe comparative TPU from example 19, they have somewhat higher hardness,but a markedly higher level of mechanical properties (modulus values andtensile strength), and also a markedly higher tensile strain value.

1.-17. (canceled)
 18. A process for the production of a thermoplasticpolyurethane elastomer comprising reacting, in a first step, at least A)one organic diisocyanate comprising two isocyanate groups with B) onepolyol with number-average molar mass M_(n)≧500 and ≦5000 g/mol, whichhas two isocyanate-reactive groups, to give an isocyanate-terminatedprepolymer, and reacting, in a second step, the prepolymer with C) oneor more chain extenders with molar mass ≧60 and ≦490 g/mol, which havetwo isocyanate-reactive groups, and optionally D) a monofunctional chainterminator which has an isocyanate-reactive group and/or optionally E)an organic diisocyanate comprising two isocyanate groups, where F) acatalyst is optionally used in the first and/or second step, the molarratio of the entirety of the isocyanate groups from A) and optionally E)to the entirety of the isocyanate-reactive groups in B), C), andoptionally D) is ≧0.9:1 and ≦1.2:1 and component B) comprises at leastone polyether carbonate polyol obtainable via an addition reaction ofcarbon dioxide and alkylene oxides onto H-functional starter substances.19. The process for the production of a thermoplastic polyurethaneelastomer as claimed in claim 18, wherein in the second step theprepolymer is reacted only with C) one or more chain extenders withmolar mass ≧60 and ≦490 g/mol, which have two isocyanate-reactivegroups, and optionally D) a monofunctional chain terminator which has anisocyanate-reactive group and/or optionally E) an organic diisocyanatecomprising two isocyanate groups.
 20. The process for the production ofa thermoplastic polyurethane elastomer as claimed in claim 18, whereinthe polyether carbonate polyol is obtainable via an addition reaction ofcarbon dioxide and alkylene oxides onto H-functional starter substanceswith the use of multimetal cyanide catalysts.
 21. The process for theproduction of a thermoplastic polyurethane elastomer as claimed in claim18, wherein the proportion of ethylene oxide in the alkylene oxides is≧0 and ≦90% by weight.
 22. The process for the production of athermoplastic polyurethane elastomer as claimed in claim 18, wherein thecontent of carbonate groups, calculated as CO₂ in the polyethercarbonate polyol is ≧3 and ≦35% by weight.
 23. The process for theproduction of a thermoplastic polyurethane elastomer as claimed in claim18, wherein the number-average molar mass M_(n) of the polyethercarbonate polyol is ≧500 and ≦10000 g/mol.
 24. The process for theproduction of a thermoplastic polyurethane elastomer as claimed in claim18, wherein the average OH functionality of the polyether carbonatepolyol is ≧1.85 and ≦2.5.
 25. The process for the production of athermoplastic polyurethane elastomer as claimed in claim 18, wherein theorganic diisocyanate A) comprises at least one aromatic diisocyanate.26. The process for the production of a thermoplastic polyurethaneelastomer as claimed in claim 18, wherein component B) comprises atleast one polyether carbonate polyol and at least one polyether polyol.27. The process for the production of a thermoplastic polyurethaneelastomer as claimed in claim 18, wherein component B) comprises atleast one polyether carbonate polyol and at least one polyester polyol.28. The process for the production of a thermoplastic polyurethaneelastomer as claimed in claim 18, wherein component B) comprises atleast one polyether carbonate polyol and at least one polycarbonatepolyol.
 29. The process for the production of a thermoplasticpolyurethane elastomer as claimed in claim 18, wherein component B)comprises two polyether carbonate polyols that differ from one another.30. The process for the production of a thermoplastic polyurethaneelastomer as claimed in claim 18, wherein component C) comprises diols,diamines, or diol/diamine mixtures.
 31. The process for the productionof a thermoplastic polyurethane elastomer as claimed in claim 18,wherein the reaction of the components takes place in a reactiveextruder or by the mixing-head-belt process.
 32. A thermoplasticpolyurethane elastomer obtained by the process as claimed in claim 18.33. A method comprising utilizing the thermoplastic polyurethaneelastomer as claimed in claim 32 for the production of injection-moldedor extruded items.
 34. An item obtained via injection molding orextrusion of the thermoplastic polyurethane elastomer as claimed inclaim 32.